The invention concerns a method and arrangement for a combined forming and machine-cutting manufacture of internally and/or externally profiled rings from pipe (tubular) material or solid material by means of radial-axial pipe roll forming in combination with turning. The method and the arrangement serve for manufacturing, inter alia, cylindrical starter rings, rolling bearing rings, and transmission rings or the like.
The manufacture of profiled rings, in particular rolling bearing rings, preferably from pipe material, is carried out either purely by machine-cutting or by a combination of machine cutting and forming.
In the case of machining purely by machine-cutting, which is very material-intensive, highly efficient multi-spindle automatic lathes can be used for a dimensional range of less than 100 mm outer diameters, wherein by single ring or multiple ring machining, preferably two ring machining, one or several, preferably two, grinding-ready profiled rings are simultaneously produced without requiring re-clamping from one machine to another.
In certain combined methods, comprised of at least two working steps on different machines, first a so-called blank, i.e., a cylindrical starter ring, beginning with pipe material or rod material, is machined also purely by machine-cutting or by a combination of machine-cutting and forming; subsequently, the blank is profiled by axial or tangential pipe roll forming to the grinding-ready state. These combined methods for producing profiled rings save more material in comparison to the purely machine-cutting processing on multi-spindle automatic lathes and are more beneficial in relation to the practical use properties but require as a result of at least one additional clamping action of the blank (starter ring) for profiling of the ring an increased expenditure in regard to working time because of the required machining on at least two different machines until a grinding-ready ring is produced. An example of such combined methods of at least two working steps is disclosed in DE 198 49 182 A1 where influencing the process-caused axial or tangential material flow is the goal. The effect on the material requires however at least two rolling steps (working steps) which is one of the already described significant disadvantages of such a manufacturing possibility.
The economic field of application of the aforementioned methods resides in particular in the dimensional range of greater than 100 mm outer diameter and concerns primarily outer and inner rings (rolling bearing rings and transmission rings) with symmetric cross-sectional shape. Moreover, there are proposed solutions (DE 197 43 055 A1, DE 199 20 163 A1) for manufacturing rings with asymmetric cross-sectional shape by tangential pipe roll forming; however, no practical use is currently known.
Further manufacturing processes for manufacturing profiled rings are based on a combination of an initial forming step by axial pipe roll forming and/or roll grooving and subsequent finishing by machine-cutting by a turning step starting from pipe material (DD 225 358 A1) or an initial machine-cutting preparation of pipe material (DD 292 162 A5) or rod steel (DD 292 161 A5) with a subsequent forming step by axial pipe roll forming and/or roll grooving as well as finishing by machine-cutting of a ring in sequence and/or in parallel on a multi-spindle automatic lathe with integrated rolling device; however, they concern exclusively externally profiled rings with symmetric or asymmetric cross-sectional shape, for example, inner rings for radial deep groove ball bearings or taper roller bearings.
In DE 195 26 900 A1 machine-cutting methods such as turning and forming methods such as axial pipe roll forming and/or roll grooving are combined in such a way that at least one ring can be profiled to a grinding-ready state by forming and/or machine-cutting simultaneously the inner side and outer side in order to enable by means of the aforementioned method combination in addition to the above described manufacture of externally profiled rings, for example, rolling bearing inner rings, also the manufacture of internally profiled rings, for example, rolling bearing outer rings.
In the case of the last-mentioned manufacturing processes, a machine is used for machine-technological realization of the method combination that enables profiling by forming of the external and internal contours of the rings with machine-cutting finishing of all further shaped elements and surface elements of the ring, including separation of the ring from the pipe as the last working stage in a process without reclamping.
Advantageously, the unmachined pipe is pre-turned by turning to size the external diameter and/or internal hollowing by turning before the forming step by axial pipe roll forming and/or roll grooving, wherein at the same time optionally required minimum cutting removal or the present edge decarburizaton of the employed starting material is taken into account.
The economic field of application of the manufacturing method for combined forming and machine-cutting processing by axial pipe roll forming/roll grooving—turning for producing profiled rings is within the dimensional range of approximately 40 to 160 mm outer diameter and comprises inner and/or outer profiled rings (rolling bearing rings and transmission rings) with symmetrical as well as asymmetrical cross-sectional shape. Moreover, the possibility of manufacturing starter rings for subsequent processing by machine-cutting or forming, for example, by axial or tangential pipe roll forming is made possible. This is advantageous particularly when the starter rings for the subsequent rolling must be pre-profiled as is mandatory in the case of complex ring geometries for axial or tangetial roll forming.
The process sequences disclosed in DD 225 358 A1, DD 292 162 A5, DD 292 161 A5, and DE 195 26 900 A1 have in common that an unhindered axial material flow occurs when axial pipe roll forming and/or roll grooving is performed. The result is that the pipe or ring during the rolling process becomes wider or longer in accordance with the material volume (up to 100%) that is being displaced by the profile of the tool. This effect is desired in the context of high material utilization and economic efficiency for ring manufacture. When processing rings having great and deep rectangular profiles (grove-like profiles), for example, in synchromesh transmission rings or selector sleeves, this effect causes problems in regard to obtaining the required precision (symmetries).
It is an object of the invention to provide a method and arrangement of the aforementioned kind with which a higher precision for the manufacture of rings with great and deep rectangular profiles (groove-like profiles), for example, in the case of synchromesh transmission rings or selector sleeves.